如何在Flask中无需新增@app.route实现会话重置？

课堂任务要求制作一个赚取金币的简易Flask游戏页面，限制最多使用2个@app.route。附加任务是添加重置按钮重新开始游戏，但现有路由无法实现该功能。尝试将按钮方法改为get并为主路由添加GET方法后仍未达到预期效果，附上代码寻求实现建议。

原Python代码 #

@app.route('/')
def index():
    if 'gold' not in session:
        session['gold'] = 0
        session['earnings'] = []
        session['losses'] = []
    if request.method == 'GET':
        session.clear
    print(session['gold'], "in the bank")
    return render_template('index.html')

@app.route('/process_money', methods=['POST'])
def process_money():
    print(request.form)
    if request.form['get_gold'] == 'rice_paddy':
        temp = random.randint(10,20)
        session['gold'] += temp
        earning = session['earnings']
        earning.append(f"Your hard work paid off, you earned {temp} gold from the rice paddy!")
        session['earnings'] = earning
        print(f"Your hard work paid off, you earned {temp} gold from the rice paddy!")
    if request.form['get_gold'] == 'hideout':
        temp = random.randint(5,10)
        session['gold'] += temp
        earning = session['earnings']
        earning.append(f"After rummaging around in the cushions, you found {temp} gold in the hideout!")
        session['earnings'] = earning
        print(f"After rummaging around in the cushions, you found {temp} gold in the hideout!")
    if request.form['get_gold'] == 'castle':
        temp = random.randint(2,5)
        session['gold'] += temp
        earning = session['earnings']
        earning.append(f"While no one was looking, you stole {temp} gold from the castle!")
        session['earnings'] = earning
        print(f"While no one was looking, you stole {temp} gold from the castle!")
    if request.form['get_gold'] == 'dice_den':
        temp = random.randint(-50,50)
        if temp >= 0:
            session['gold'] += temp
            earning = session['earnings']
            earning.append(f"Nice! You gained {temp} gold while gambling at the dice den!")
            session['earnings'] = earning
            print(f"Nice! You gained {temp} gold while gambling at the dice den!")
        elif temp <= 0:
            session['gold'] += temp
            losses = session['losses']
            losses.append(f"Aww, too bad! You lost {temp} gold while gambling at the dice den!")
            session['losses'] = losses
            print(f"Aww, too bad! You lost {temp} gold while gambling at the dice den!")
    return redirect('/')

if __name__ == "__main__":
    app.run(debug=True)

原HTML代码 #

<body>
    <div id="main" class="container bg-dark">
        <label for="your_gold" class="text-light" style="margin-top: 1.5rem;">Your Gold:</label>
        <input type="number" value="{{session['gold']}}">
        <div class="d-flex">
            <div class="container">
                <form method="post" action="/process_money">
                    <input type="hidden" name="get_gold" value="rice_paddy">
                    <h4>Rice Paddy</h4>
                    <p>(earns 10-20 gold)</p>
                    <input type="submit" name="rice_paddy" id="rice_paddy" value="Earn Gold!">
                </form>
            </div>
            <div class="container">
                <form method="post" action="/process_money">
                    <input type="hidden" name="get_gold" value="hideout">
                    <h4>Hideout</h4>
                    <p>(earns 5-10 gold)</p>
                    <input type="submit" name="hideout" id="hideout" value="Find Gold!">
                </form>
            </div>
            <div class="container">
                <form method="post" action="/process_money">
                    <input type="hidden" name="get_gold" value="castle">
                    <h4>Shiro</h4>
                    <p>(earns 2-5 gold)</p>
                    <input type="submit" name="castle" id="castle" value="Steal Gold!">
                </form>
            </div>
            <div class="container">
                <form method="post" action="/process_money">
                    <input type="hidden" name="get_gold" value="dice_den">
                    <h4>Dice Den</h4>
                    <p>(earns/takes 0-50 gold)</p>
                    <input type="submit" name=dice_den id=dice_den value="Gamble Gold!">
                </form>
            </div>
        </div>
        <h5 class="text-light">Activities:</h5>
        <div id="activities" class="container">
            <ul>
                    {% for earning in session['earnings'] %}
                        <li class="text-success">{{earning}}</li>
                    {% endfor %}
                    {% for loss in session['losses'] %}
                        <li class="text-danger">{{loss}}</li>
                    {% endfor %}
            </ul>
        </div>
        <a method='get' class="btn btn-danger" style="border: 2px solid black; width: auto; margin-bottom: 20px;" href="/">Reset</a>
    </div>
</body>
</html>

问题分析 #

1. session.clear是方法调用，缺少括号，正确写法是session.clear()，否则不会执行清除操作。
2. 原主路由中每次GET请求都清除session，导致用户正常访问页面时也会重置游戏，逻辑错误。
3. HTML中的<a>标签的method属性无效，GET请求无法通过该属性控制，需要通过查询参数区分重置请求。

修改步骤 #

1. 调整主路由逻辑：添加查询参数reset，仅当request.args.get('reset')存在时清除session，之后重新初始化游戏数据。
2. 修正session调用：将session.clear改为session.clear()。
3. 修改重置按钮链接：将链接改为/?reset=true，触发重置逻辑。

修改后的Python代码 #

from flask import Flask, render_template, request, redirect, session
import random

app = Flask(__name__)
app.secret_key = 'your_secret_key_here'  # 必须设置密钥，session才能正常工作

@app.route('/')
def index():
    # 处理重置请求
    if request.args.get('reset'):
        session.clear()
    
    # 初始化session数据（如果不存在）
    if 'gold' not in session:
        session['gold'] = 0
        session['earnings'] = []
        session['losses'] = []
    
    print(session['gold'], "in the bank")
    return render_template('index.html')

@app.route('/process_money', methods=['POST'])
def process_money():
    print(request.form)
    if request.form['get_gold'] == 'rice_paddy':
        temp = random.randint(10,20)
        session['gold'] += temp
        earning = session['earnings']
        earning.append(f"你的努力有回报了！从稻田赚了{temp}金币！")
        session['earnings'] = earning
    elif request.form['get_gold'] == 'hideout':
        temp = random.randint(5,10)
        session['gold'] += temp
        earning = session['earnings']
        earning.append(f"翻遍垫子后，你在藏身处找到了{temp}金币！")
        session['earnings'] = earning
    elif request.form['get_gold'] == 'castle':
        temp = random.randint(2,5)
        session['gold'] += temp
        earning = session['earnings']
        earning.append(f"趁没人注意，你从城堡偷了{temp}金币！")
        session['earnings'] = earning
    elif request.form['get_gold'] == 'dice_den':
        temp = random.randint(-50,50)
        if temp >= 0:
            session['gold'] += temp
            earning = session['earnings']
            earning.append(f"不错！在骰子馆赌博赢了{temp}金币！")
            session['earnings'] = earning
        else:
            session['gold'] += temp
            losses = session['losses']
            losses.append(f"哎呀太糟了！在骰子馆赌博输了{abs(temp)}金币！")
            session['losses'] = losses
    return redirect('/')

if __name__ == "__main__":
    app.run(debug=True)

修改后的HTML代码 #

<body>
    <div id="main" class="container bg-dark">
        <label for="your_gold" class="text-light" style="margin-top: 1.5rem;">你的金币:</label>
        <input type="number" value="{{session['gold']}}" readonly> <!-- 设为只读防止手动修改 -->
        <div class="d-flex">
            <div class="container">
                <form method="post" action="/process_money">
                    <input type="hidden" name="get_gold" value="rice_paddy">
                    <h4>稻田</h4>
                    <p>(赚取10-20金币)</p>
                    <input type="submit" name="rice_paddy" id="rice_paddy" value="赚取金币！">
                </form>
            </div>
            <div class="container">
                <form method="post" action="/process_money">
                    <input type="hidden" name="get_gold" value="hideout">
                    <h4>藏身处</h4>
                    <p>(赚取5-10金币)</p>
                    <input type="submit" name="hideout" id="hideout" value="寻找金币！">
                </form>
            </div>
            <div class="container">
                <form method="post" action="/process_money">
                    <input type="hidden" name="get_gold" value="castle">
                    <h4>城堡</h4>
                    <p>(赚取2-5金币)</p>
                    <input type="submit" name="castle" id="castle" value="偷取金币！">
                </form>
            </div>
            <div class="container">
                <form method="post" action="/process_money">
                    <input type="hidden" name="get_gold" value="dice_den">
                    <h4>骰子馆</h4>
                    <p>(赢取/损失0-50金币)</p>
                    <input type="submit" name=dice_den id=dice_den value="赌博金币！">
                </form>
            </div>
        </div>
        <h5 class="text-light">活动记录:</h5>
        <div id="activities" class="container" style="height: 200px; overflow-y: auto; background-color: white; padding: 10px;">
            <ul>
                    {% for earning in session['earnings'] %}
                        <li class="text-success">{{earning}}</li>
                    {% endfor %}
                    {% for loss in session['losses'] %}
                        <li class="text-danger">{{loss}}</li>
                    {% endfor %}
            </ul>
        </div>
        <a class="btn btn-danger" style="border: 2px solid black; width: auto; margin-bottom: 20px; margin-top: 10px;" href="/?reset=true">重置游戏</a>
    </div>
</body>
</html>

额外优化说明 #

• 添加了app.secret_key，Flask的session必须设置密钥才能正常使用。
• 将金币输入框设为readonly，防止用户手动修改金币数值。
• 给活动记录框添加了滚动条和背景色，提升可读性。
• 将英文文本翻译成中文，更符合使用习惯。

内容的提问来源于stack exchange，提问作者Brad